Structural support beams

ABSTRACT

The invention relates to structural support beams for use in building and construction, which possess structural characteristics suitable for use as load-bearing flexural members. The support beam comprises a timber support frame formed from two spaced apart flanges connected by at least two outer support webs. Optionally one or more further inner support webs connect the flanges in an intermediate position between the outer support webs. Together, the flanges and support webs define at least one volume which is filled with a plastics foam material to provide both improved structural and sound/thermal insulation properties. The use of regular rectangular flanges, which are fully interposed between outer support webs, provides a stronger and stiffer support beam both in bending and in shear. In fact, the absence of grooves, recesses or cutout portions in the flanges provides further advantages such as greater dimensional stability, ease of construction and cheaper and simpler manufacturing. The support beams may be in the form of I-beams, double I-beams, box-beams, boxed I-beams or boxed double I-beams.

This invention relates to a structural support beam manufactured from acomposite of materials, and in particular, but not exclusively, to acomposite of timber in various forms with an infill of material thatprovides both added structural support and thermal/sound insulation, foruse in the building and construction industry.

Support beams of the form of Laminate Veneer Lumber (LVL), Parallamproducts, Glulam products, I-joists and Box Beams, are known. Thesedifferent support beams offer different structural properties and areused in different designs for different applications. For example,Parallam products have a high stiffness and strength compared to theother above-mentioned beams, but are heavier, more abrasive to saw anddrill, require connection be made to adjacent beams with metal platesand bolts or dowels rather than nails, and are relatively costly; LVLproducts provide strength and consistent performance, are easy to workwith, can be cut and nailed on site, resist shrinkage, warping,splitting and checking, but are relatively costly.

Box beams are also known as shown in FIG. 1. These typically consist ofsolid timber or LVL flanges with plywood or Oriented Strand Board (OSB)webs. The webs are glued and/or mechanically connected to the flanges oneach side to form a box shape.

Box beams are moderately lightweight, can be handled easily, allow ahigher load capacity than comparable sized timber, resist shrinkage,warping and checking and are more efficient than solid timber for largespans and loads.

However, such box beams are susceptible to shear buckling and thereforerequire web stiffeners to be positioned at points of increased load tocounter localised web buckling. Furthermore, holes in the web can onlybe located where shear loads are low.

According to a first aspect of the present invention there is provided astructural support beam for use in building and construction comprisinga support frame defining at least one volume, said support frame beingof a first material and said at least one volume being in-filled with asecond material.

Preferably, the support frame comprises two spaced apart flangesconnected by at least two outer support webs.

Preferably, each outer support web connects lateral portions of theflanges.

Optionally, one or more additional outer support web(s) is/arepositioned over one or both of the existing outer support webs.

Preferably, one or more inner support webs connect the flanges in anintermediate position between the outer support webs.

Optionally, one or more formations are provided in each flange toaccommodate the outer support webs. Optionally, one or more formationsare provided in each flange to accommodate the inner support web orwebs.

Preferably, the formations are one or more of grooves, recesses andcut-out portions.

Preferably, the flanges are rectangular in shape.

Preferably, each flange is fully interposed between the outer supportwebs.

Optionally, each flange is provided with a reduced width portion todefine a T-shaped flange.

Preferably, each reduced width portion is fully interposed between theouter support webs.

Preferably, the lateral edges of the other portions are adapted to beflush with the outer surfaces of the outer support webs.

Alternatively, the lateral edges of the other portions are adapted toextend beyond the outer surfaces of the outer support webs.

Optionally, a further end-flange is connected to the outer end of eachexisting flange.

Preferably, the lateral edges of each end-flange are adapted to be flushwith the outer surfaces of the outer support webs.

Alternatively, the lateral edges of each end-flange are adapted toextend beyond the outer surfaces of the outer support webs.

Optionally, metal end plates are connected to the outer end of eachflange.

Optionally or additionally, the metal end plates are connected to theouter end of each end-flange.

Preferably, the second material is less dense than the first material.

Preferably, the second material is a plastics foam material.

Preferably, the second material is adapted to give the support beamimproved thermal and/or sound insulating properties.

Alternatively or additionally, the second material is adapted to givethe support beam improved structural properties.

Preferably, the support frame is made from timber materials.

According to a second aspect of the present invention there is provideda structural support beam for use in building and constructioncomprising a timber based support frame formed from two spaced apartrectangular flanges connected by at least two outer support webs whereinthe timber based support frame defines at least one volume in-filledwith a plastics foam material; and wherein the plastics foam material isbonded to the flanges and webs.

Preferably, the outer support webs extend over the full depth of theflanges.

Preferably, the flanges are formed from solid or laminated timbermaterial and the webs are formed from timber sheet material.

According to a third aspect of the present invention there is provided amethod of manufacturing the structural support beam of the first aspect,said method comprising the steps of:

-   -   (i) connecting two spaced apart flanges by means of at least two        outer support webs to form a support frame defining at least one        volume; and    -   (ii) filling said at least one volume with an in-fill of        material.

Preferably, the method comprises the additional step of bonding saidin-fill of material to the support frame.

Preferably, the method comprises the further additional step of gluingand/or mechanically fixing the outer support webs to the flanges.

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a known box beam;

FIG. 2 is a cross-sectional view of a support beam made in accordancewith the present invention;

FIGS. 3 a-b are cross-sectional views of the apparatus of FIG. 2 withadditional end-flanges to form an I-beam showing fasteners visible fromthe outside, and not visible from the outside, respectively;

FIGS. 4 a-b are cross-sectional views of the apparatus of FIG. 2 withadditional end-flanges to form a box beam showing fasteners visible fromthe outside, and not visible from the outside, respectively;

FIG. 5 a is a cross-sectional view of the apparatus of FIG. 2 with anadditional inner support web;

FIG. 5 b is a cross-sectional view of the apparatus of FIG. 2 with twoadditional inner support webs;

FIGS. 5 c-d are cross-sectional views showing alternative profiles ofthe connections of the inner support webs to the flanges.

FIGS. 6 a-b are cross-sectional views of the apparatus of FIG. 2 with anadditional lateral support web connected to one and both of the outerface(s) respectively of the apparatus of FIG. 2;

FIG. 7 is a cross-sectional view of an alternative support beam havingT-flanges to form an I-beam;

FIG. 8 is a cross-sectional view of an alternative support beam havingT-flanges to form a box beam;

FIG. 9 is a cross-sectional view of an alternative beam support havinggrooved flanges to form an I-beam;

FIG. 10 is a cross-sectional view of a further alternative beam supporthaving recessed flanges to form an I-beam;

FIG. 11 is a cross-sectional view of an alternative support beam havingrectangular flanges to form an I-beam;

FIG. 12 is a cross-sectional view of the apparatus of FIG. 11 havingadditional supports at the junctions between the flanges and the lateralsupport webs;

FIG. 13 shows cross-sectional views of adapted embodiments of thepresent invention: (a) is the apparatus of FIG. 2 with metal end platesadded to the flanges; (b) is the apparatus of FIG. 3 a having metal endplates added to the flanges; (c) is an alternative arrangement to (b);(d) is the apparatus of FIG. 8 with metal end plates added to theflanges; (e) is the apparatus of FIG. 9 with metal end plates added tothe flanges; (f) is the apparatus of FIG. 5 adapted with both additionalend-flanges and metal end plates;

FIG. 14 is a comparison of the load-deformation characteristics of asample of embodiments made in accordance with the present inventionunder direct compression loads; and

FIG. 15 is a qualitative table comparing known support beams to those ofthe present invention.

Referring to the drawings, FIG. 1 shows a known box beam 10 consistingof two spaced apart horizontal flanges 16, 18 connected by therespective ends of two opposing vertical webs 12, 14 to form a boxshape. Typically, the webs 12, 14 are glued to the flanges 16, 18 and/ormechanically connected during manufacture. Throughout the specification,the term “box beam” is used to refer to a beam having an overallrectangular shape.

In a first embodiment of the present invention, as shown in FIG. 2,there is a structural support beam in the form of a box beam 100. Theterm “structural support beam” used throughout the specification isintended to refer to support beams possessing structural characteristicssuitable for use as load-bearing flexural members. The structuralsupport beam comprises two flanges 116, 118 connected by the respectiveends of two opposing laterally arranged vertical support webs 112, 114to form a support frame in the shape of a box.

The outer support webs 112, 114 are glued and or mechanically connectedto the flanges 116, 118. Typically, the flanges are of solid sawntimber, Glulam or LVL, and the webs are of a timber sheet product suchas plywood or Oriented Strand Board (OSB).

The box beam 100 further includes an infill of support/insulatingmaterial 110 within a volume defined by the outer support webs 112, 114and flanges 116, 118. The material 110 is less dense than the timbermaterial from which the flanges and outer support webs are formed.

The material 110 is a plastics foam, for example, expanded polystyrene(EPS), extruded polystyrene, urethane, or other similar insulation coresthat are bonded to the outer support webs 112, 114 and flanges 116, 118to form a close contact. The material 110 may be of any type to improveboth the insulation (thermal and/or sound) and/or structural propertiesof the box beam 100. The material 110 may be bonded to the interiorsurfaces of the outer support webs 112, 114 and the flanges 116, 118.

In a second embodiment of the present invention, as shown in FIGS. 3a-b, there is a structural support beam in the form of an I-beam 200comprising substantially the same box beam 100 as described above withthe addition of further end-flanges 220, 222 (which will hereinafter bereferred to as I-flanges) connected to flanges 116, 118 (which willhereinafter be referred to as box-flanges) to form an I-shaped supportframe. The I-flanges 220, 222 are glued and/or mechanically connected tothe box-flanges 116, 118. Mechanical connectors can either be locatedthrough the I-flanges to the box-flanges as shown in FIG. 3 a or can belocated from the box-flanges to the I-flanges as shown in FIG. 3 b so asnot to be visible from the outer surface of the I-beam 200.

In a third embodiment of the present invention, as shown in FIGS. 4 a-b,there is a structural support beam in the form of a box beam 300comprising substantially the same box beam 100 as described above withthe addition of further end-flanges 320, 322 (hereinafter referred to asflush-flanges) the lateral edges of which are adapted to be flush withthe outer surfaces of the opposing laterally arranged outer support websto form a box beam. The flush-flanges 320, 322 are glued and/ormechanically connected to the box-flanges 116, 118. Mechanicalconnectors can either be located through the flush-flanges to thebox-flanges as shown in FIG. 4 a or can be located from the box-flangesto the flush-flanges as shown in FIG. 4 b so as not to be visible fromthe outer surface of the box beam 300.

In a fourth embodiment of the present invention, as shown in FIG. 5 a,there is a structural support beam in the form of a boxed I-beam 400comprising substantially the same box beam 100 as described above withthe addition of a further inner support web 424 connecting box flanges416, 418. The inner support web 424 lies parallel with the opposingouter support webs 112, 114 in an intermediate position between theouter support webs. The box flanges 416, 418 are each provided with agroove 426, 428, each groove being adapted to receive a respective endof the inner support web 424 and retain it in position within therespective box flanges 416, 418. The web 424 may be rigidly fittedwithin the grooves 426, 428 and/or glued and/or mechanically connected.FIG. 5 b shows a structural support beam as described in the previousparagraph having two inner support webs 424 to form a boxed doubleI-beam. The in-fill material may be bonded to the interior surfaces ofthe outer support webs 112, 114 and the flanges 116, 118 and to bothsurfaces of the inner support web(s).

FIGS. 5 c-d show alternative profiles of the connections between theinner support webs 424 and the grooves 426, 428. FIG. 5 c shows an innersupport web 424 having a rectangular end profile and FIG. 5 d shows aninner support web having a tapered end profile.

In a fifth embodiment of the present invention, as shown in FIGS. 6 a-b,there is a structural support beam in the form of a box beam 500comprising substantially the same box beam 100 as described above withadditional laterally arranged outer support webs 513, 515 beingconnected to the outer surface of one or both outer support webs 112,114. The additional laterally arranged outer support webs 513, 515 couldbe glued and/or mechanically connected to their respective outer supportwebs 112, 114.

In a sixth embodiment of the present invention, as shown in FIG. 7,there is a structural support beam in the form of an I-beam 600comprising two T-shaped flanges 616, 618, (T-flange 616 being inverted),connected by the respective ends of two opposing outer support webs 612,614 to form an I-shaped support frame. Each T-shaped flange comprises areduced diameter stem portion. The stem portions are formed by cuttingaway two rectangular corner portions from a regular rectangular flange.The outer support webs 612, 614 can be glued and/or mechanicallyconnected to the lateral sides of the stem portions of the T-shapedflanges 616, 618. The outer support webs 612, 614 and flanges 616, 618define a volume having an infill of support/insulating material 610substantially the same as material 110 as hereinbefore described.

In a seventh embodiment of the present invention, as shown in FIG. 8,there is a structural support beam in the form of a box beam 700comprising two T-shaped flanges 716, 718, (T-flange 716 being inverted),the lateral edges of which are adapted to be flush with the outersurfaces of the opposing outer support webs 712, 714 to form a box beam.The outer support webs 712, 714 can be glued and/or mechanicallyconnected to the stem portions of the T-shaped flanges 716, 718. Thewebs 712, 714 and flanges 716, 718 define a volume having an infill ofsupport/insulating material 710 substantially the same as material 110as hereinbefore described.

In an eighth embodiment of the present invention, as shown in FIG. 9,there is a structural support beam in the form of an I-beam 800comprising two double grooved flanges 816, 818 connected by therespective ends of two opposing outer support webs 812, 814 to form anI-shaped support frame. The respective outer support webs 812, 814 areeach located within grooves 824 a-826 b provided on the double groovedflanges 816, 818. The outer support 812, 814 may be rigidly fittedwithin grooves 824 a-826 b and/or glued and/or mechanically fastened tothe double grooved flanges 816, 818. The outer support webs 812, 814 anddouble grooved flanges 816, 818 define a volume having an infill ofsupport/insulating material 810 substantially the same as material 110as hereinbefore described.

In a ninth embodiment of the present invention, as shown in FIG. 10, theI-beam 800 has been adapted to form a new structural support beam orI-beam 900. Single recesses 925, 927 replace the double grooves 824a-826 b of the flanges 816, 818. The outer support webs 812, 814 can beaccommodated within part of each single recess 925, 927 and an infill ofsupport/insulating material 910 substantially the same as material 110as hereinbefore described is provided in the volume defined by the outersupport webs and the single recessed flanges.

In a tenth embodiment of the present invention, as shown in FIG. 11,there is a structural support beam in the form of an I-beam 1000comprising two rectangular I-flanges 1016, 1018 connected betweenrespective ends of two outer support webs 1012, 1014 to form an I-shapedsupport frame. The outer support webs 1012, 1014 and flanges 1016, 1018define a volume having an infill of support/insulating material 1010substantially the same as material 110 as hereinbefore described.

In an eleventh embodiment of the present invention, as shown in FIG. 12,the I-beam 1000 has been adapted to form a new structural support beamor I-beam 1100, wherein, support members 1101-1104 are glued and/ormechanically connected at the junction region between the ends of outersupport webs 1012, 1014 and the I-flanges 1016, 1018.

It will be appreciated by those skilled in the art that mechanicalfixing of the outer support webs and flanges can be carried out by anysuitable means, for example by nails, staples, screws, bolts etc.

It will further be appreciated that each of the foregoing embodimentscan be adapted or modified to include features of any of the otherembodiments. For example, the additional inner support web(s) of FIGS. 5a-b may be easily incorporated into any of the other embodiments.Equally, any one of the embodiments can easily be modified or adapted togive improved structural properties. For example, FIG. 13 shows how someof the embodiments may be fitted with metal plates to improve theirstructural characteristics.

Moreover, it will be appreciated by those skilled in the art that theintegrity of the flanges affects the structural qualities of a supportbeam. In particular, the connection of the outer support webs to theflanges is an important area in terms of structural integrity. Forexample, the absence of grooves, recesses and cut out portions inotherwise rectangular shaped flanges (e.g. see FIGS. 2-4, 6 and 11-13 c)offers several advantages. By rectangular, it is meant that the flangesare of a regular four-sided rectangular or square shape without anyformations such as grooves recesses or cut-out portions to accommodatethe outer support webs. Rectangular flanges offer several advantages asfollows: (i) Ease of Construction—the simplicity of the design avoidsthe need for expensive grooving and close tolerances; (ii) Strength andStiffness—the presence of grooves or recesses within the flanges createsareas of weakness and hence reduces the bending and longitudinal shearstrength capacity of the structural beam. For a set beam depth (oftengoverning the design and detailing criteria), a box shaped design suchas that shown in FIG. 2 will provide a stronger beam in bending (due tothe fully intact flanges) and in shear (due to outer support websextending to the full depth of the flanges) and therefore an overallstiffer solution; (iii) Greater Dimensional Stability—the absence ofgrooving increases dimensional stability and reduces the possibilitiesfor differential shrinkage in flanges which can lead to cracking; and(iv) Cost—grooving is an expensive part of the manufacturing processboth in terms of preparation and assembly as specialised jigs and clampsare required. The exclusion of grooves and recesses thus leads to alower cost solution with the added benefit of performance gains.

The support beams of the present invention incorporate both structuraland insulation qualities into a single member during manufacture thusachieving higher quality, more accurate thermal and/or sound efficiencyand an increased level of structural support.

The structural beams of the present invention can also be produced invarying sizes and thickness depending on the particular application andinsulation/structural requirements.

The material 110-1010 not only provides thermal and/or sound insulation,but also provides increased structural properties as demonstrated byFIG. 14, the results of which are described below.

Samples of the aforementioned embodiments described above have beentested (under static compression) to establish their structuralproperties. The apparatus tested was:

(A) and (B) which are the support beams of FIGS. 2 and 1, i.e. with andwithout the infill of material 110 respectively;

(C) and (D) which are the support beam of FIG. 9 and a correspondingsupport beam without an infill of material respectively;

(E) and (F) which are the support beams of FIG. 5 a and a correspondingsupport beam without an infill of material respectively; and

(G) and (H) which are the support beams of FIG. 8 and a correspondingsupport beam without an infill of material respectively.

For all support beams, corresponding flanges were cut from Whitewoodgrade C16 timber. The corresponding outer support webs were cut from 11mm thick OSB grade 3 panels and the infill material was 95 mm thickexpanded polystyrene (EPS). All contact surfaces were glued together,and where appropriate, were screwed using 2×8 woodscrews.

In comparing the support beams with the infill of material (A, C, E andG) and without the infill of material (B, D, F and H), there isgenerally an increase in the ultimate load capacity and ductility of thesupport beams having the infill of material.

Advantageously, the infill material adds very little overall weight toeach support beam, yet it provides a significantly increased ultimateload capacity.

Furthermore, the requirement for I-beams and box beams to have webstiffeners at areas prone to localised buckling may be dispensed withdue to the increased ultimate load capacity of the support beams havingthe infill of material.

Moreover, the results shown in FIG. 14 show that the support beamshaving the infill of material (A, C, E, G) can carry the same load foran increased deflection/displacement, i.e. they have enhanced ductilityqualities.

In particular, supports beams (C) and (D) are worthy of further comment.The infill of material in support beam (C) exhibits an interestingquality in that it appears to affect the failure mode of the supportbeam. Although support beam (D) appears to fail suddenly at adisplacement of approximately 4 mm, support beam (C) appears toinitially fail at a displacement of approximately 5 mm yet can stillhold the load applied for a further 4 mm of displacement. This shows thelevel of enhanced ductility provided by the infill material of supportbeam (C).

Overall the results clearly demonstrate that the addition of an innersupport web connected between the flanges within the infill of materialexhibit a far higher ultimate load capacity. From this result, it can beextrapolated that the addition of one or more inner support web(s) mayincrease the ultimate load capacity of any support beam design.

Having conducted the above tests, FIG. 15 shows a qualitative comparisonof the structural support beams of the present invention with knowndesigns.

The structural support beams of the present invention may be used in anybuilding and construction projects. The support beams may be in the formof I-beams, double I-beams, box-beams, boxed I-beams or boxed doubleI-beams.

Modifications and improvements may be made to the above withoutdeparting from the scope of the present invention. For example, theinfill material 110-1010 may be pre-fabricated, in which case, therespective outer support webs and flanges of a support frame may bebonded directly to the pre-fabricated material 110-1010. The infillmaterial may be formed from either open cell, closed cell or a mixtureof open and closed cell foam materials. Alternatively, the infillmaterial may be formed from a wood-based material or any other suitablematerial providing the desired structural and/or thermal/soundinsulating properties.

Alternatively, the material 10-1010 may be injected into a volumedefined by a support frame of outer support webs and flanges, whereinthe material expands to fill the volume. The respective contact surfaceof the support frame may have bonding means to assist on securing andensuring a close contact with the infill of material 10-1010 to thesupport frame.

1. A structural support beam for use in building and constructioncomprising a support frame defining at least one volume, said supportframe being of a first material and said at least one volume beingin-filled with a second material.
 2. A structural support beam asclaimed in claim 1, wherein the support frame comprises two spaced apartflanges connected by at least two outer support webs.
 3. A structuralsupport beam as claimed in claim 2, wherein each outer support webconnects lateral portions of the flanges.
 4. A structural support beamas claimed in claim 2, wherein one or more additional outer supportweb(s) is/are positioned over one or both of the existing outer supportwebs.
 5. A structural support beam as claimed in claim 2, wherein one ormore inner support webs connect the flanges in an intermediate positionbetween the outer support webs.
 6. A structural support beam as claimedin claim 2, wherein one or more formations are provided in each flangeto accommodate the outer support webs.
 7. A structural support beam asclaimed in claim 5, wherein one or more formations are provided in eachflange to accommodate the inner support web or webs.
 8. A structuralsupport beam as claimed in claim 6, wherein the formations are one ormore of grooves, recesses and cut-out portions.
 9. A structural supportbeam as clamed in claim 2, wherein the flanges are rectangular in shape.10. A structural support beam as claimed in claim 9, wherein each flangein fully interposed between the outer support webs.
 11. A structuralsupport beam as claimed in claim 2, wherein each flange is provided witha reduced width portion to define a T-shaped flange.
 12. A structuralsupport beam as claimed in claim 11, where in each reduced width portionis fully interposed between the outer support webs.
 13. A structuralsupport beam as claimed in claim 11, wherein the lateral edges of theother portions are adapted to be flush with the outer surfaces of theouter support webs.
 14. A structural support beam as claimed in claim11, wherein the lateral edges of the other portions are adapted toextend beyond the outer surfaces of the outer support webs.
 15. Astructural support beam as claimed in claim 2, wherein a furtherend-flange is connected to the outer end of each existing flange.
 16. Astructural support beam as claimed in claim 15, wherein the lateraledges of each end-flange are adapted to be flush with the outer surfacesof the outer support webs.
 17. A structural support beam as claimed inclaim 15, wherein the lateral edges of each end-flange are adapted toextend beyond the outermost surfaces of the outer support webs.
 18. Astructural support beam as claimed in claim 2, wherein metal end platesare connected to the outer end of each flange.
 19. A structural supportbeam as claimed in claim 15, wherein metal end plates are connected tothe outer end of each end-flange.
 20. A structural support beam asclaimed in claim 1, wherein the second material is less dense than thefirst material.
 21. A structural support beam as claimed in claim 1,wherein the second material is a plastics foam material.
 22. Astructural support beam as claimed in claim 1, wherein the secondmaterial is adapted to give the support beam improved thermal and/orsound insulating properties.
 23. A structural support beam as claimed inclaim 1, wherein the second material is adapted to give the support beamimproved structural properties.
 24. A structural support beam as claimedin claim 1, wherein the support frame is made from timber materials. 25.A structural support beam for use in building and constructioncomprising a timber based support frame formed from two spaced apartrectangular flanges connected by at least two outer support webs whereinthe timber based support frame defines at least one volume in-filledwith a plastics foam material; and wherein the plastics foam material;and wherein the plastics foam material is bonded to the flanges andwebs.
 26. A structural support beam as claimed in claim 25, wherein theouter support webs extend over the full depth of the flanges.
 27. Astructural support beam as claimed in claim 25, wherein the flanges areformed from solid or laminated timber material and the webs are formedfrom timber sheet material.
 28. A method of manufacturing the structuralsupport beam of claim 1, said method comprising the steps of: (i)connecting two spaced apart flanges by means of at least two outersupport webs to form a support frame defining at least one volume; and(ii) filling said at least one flume with an in-fill of material. 29.The method of claim 25, further comprising the additional step ofbonding said in-fill of material to the support frame.
 30. The method ofclaim 25, further comprising the additional step of gluing and/ormechanically fixing the outer support webs to the flanges.